Some really interesting plants are weeds. 

Ornamental thistle, like the one below, has a wonderfully round head of pale lavender whirligigs.  Its leaves are coarse, but its flowerheads are striking.

Another interesting weed is this burr plant.                                        

This plant is growing at the edge of my compost piles and is definitely a weed! But it had  such intriguing blooms that I’ve let it live–for now.                                                     

And of course milkweed is, by definition, a weed.  The one above is a cultivated, narrow-leaved version of the wild ones that used to provide such a reliable food source for Monarch butterflies.  Now, with intense farming, milkweed-filled ditches are unfortunately far less common here in Minnesota.  I haven’t seen any Monarchs this year.  But if they still come, I’ll be ready.  The adult Monarchs hang off these Joe Pye Weeds by the dozens in late August.                                                                                                                        If they still come, the weeds and I will be waiting.  Sometimes in gardening, that’s the best you can do.